1. Field of the Invention
The present invention relates to an information input device, an image forming apparatus, a position determination method, and a position determination program. Particularly, the present invention relates to the input of operations information to an image forming mechanism.
2. Description of the Related Art
In recent years and continuing to the present, the digitization of information has become pervasive. Therefore, image processing apparatuses such as printers and facsimile machines used for outputting digitized information and scanners used for digitizing documents are indispensable. In many cases, such image processing apparatuses are configured as multi-function peripherals that can serve as printers, facsimile machines, scanners, and copiers because they have an image pickup function, an image forming function, a communication function, etc.
Such image processing apparatuses are provided with an operations unit for inputting information corresponding to the various functions described above. Generally, the operations unit serving as a switching unit, which is used for switching the mechanisms of the printer, facsimile machine, scanner, copier, etc., uses a tact key system.
However, since the image processing apparatuses have gone multifunctional in recent years, they should have many operational functions installed therein. Therefore, the number of tact keys to be provided increases, which in turn makes it difficult for users to operate the image processing apparatuses. In addition, a space for arranging the tact keys is limited in the image processing apparatuses. On the other hand, if the limited number of tact keys are used for implementing all the operations, many operations are allocated to each of the tact keys, which in turn also makes it difficult for the users to operate the image processing apparatuses.
Meanwhile, as another mode of the operations unit, a touch panel may be used. In the touch panel, a display screen for displaying information is integrated with an operations unit serving as an input unit for inputting information, and users input information by touching the display screen of the touch panel with a finger, a dedicated pen, etc. When the users switch the display of the display screen, various screens serving as an input screen for inputting information can be realized on the touch panel.
In such a touch panel, various information input units are configured on a limited display screen. Therefore, there is disclosed an example in which multiple switches, which serve as sensors and are turned on by the contact of a finger or a dedicated pen, are arranged in a lattice pattern. In this example, information corresponding to each screen is input when a display screen is switched (see, e.g., Patent Document 1).
Thus, in the touch panel, various screens serving as input screens for inputting information can be implemented in such a manner that the display of the display screen is switched. Therefore, when the switching unit is configured by the touch panel, problems in operationality and an installation space can be addressed.
However, according to the touch panel using the method disclosed in Patent Document 1, a touched position is detected based on the arrangement positions of the switches serving as sensors. Therefore, in case that a position between the switches is touched, the touched position cannot be accurately detected. In other words, if an area surrounded by four sensors rather than the upper parts of the sensors is touched by a finger or a dedicated pen, it is not possible to determine which one of the sensors is touched. In order to improve accuracy in detecting a touched position, an arrangement interval between the sensors must be finely adjusted. In this case, however, the number of sensors increases, which in turn increases a manufacturing cost.
Such a problem is not limited to a case where the switching unit is configured by the touch panel, but it could also be caused in a touch panel applied to the main operations screen of an image processing apparatus. Further, such a problem could also be caused not only in the operations unit of the image processing apparatus but also in portable information processing apparatuses such as mobile phones and PDAs (Personal Data Assistants) that have an information input device integrated with a display screen.
Patent Document 1: JP-A-2002-182835